Fermented soybean products, such as fermented bean curd, black beans, soybean paste, and soy sauce, are widely favored as condiments and accompaniments for meals. Research from modern medicine and food science has revealed that besides the inherent nutritional and health-promoting components of soybeans—such as high-quality protein, isoflavones, soybean oligosaccharides, saponins, lecithin, linoleic acid, linolenic acid, and abundant calcium and iron—fermentation further enhances the following health benefits:
1. Fermented soybean products are rich in nutrients and easy to digest. The fermentation process generates a large amount of oligopeptides, which have multiple physiological health functions, including anti-aging, cancer prevention, blood lipid reduction, and insulin regulation, making them highly beneficial to health.
2. They can lower blood cholesterol concentration and reduce the risk of coronary heart disease. Fermented soybean products are rich in aglycone-type isoflavones, which are converted from the isoflavones originally present in soybeans and tofu through fermentation. These converted isoflavones are more functional and easier to absorb than their original forms. Just 60 grams of black beans, 60 grams of soybean paste, or 100 grams of fermented bean curd contain 50 milligrams of high-activity isoflavones, reaching the U.S. Food and Drug Administration's recommended daily intake for preventing coronary heart disease.[China Cuisine]
3. They have the function of lowering blood pressure. Internationally, blood pressure-lowering peptides for health foods are produced by chemically decomposing soy protein. Our experiments have found that traditional Chinese black beans and fermented bean curd contain high-activity blood pressure-lowering peptides. In fact, during fermentation, microorganisms first break down soy protein into smaller molecules, which are known as peptides.
4. They can help prevent osteoporosis. The isoflavones in fermented soybean products can increase the activity of osteoblasts and promote the production of insulin-like growth factors, thereby preventing osteoporosis. A nutritional survey in Japan found that people who drink miso soup or consume fermented soybean products daily have a significantly lower incidence of osteoporosis, especially among the elderly and women.
5. The author's research has found that the antioxidant components in tofu, such as vitamin E, isoflavones, and other phenolic substances, as well as certain peptides, give tofu the ability to scavenge free radicals. Furthermore, fermented bean curd produced through fermentation has a 5 to 10 times greater ability to scavenge free radicals than tofu, and over 10 times greater than fruits and vegetables like tomatoes and grapes.
6. Black beans contain a large amount of nattokinase, which can dissolve blood clots, and are also rich in bacteria that produce a large quantity of B vitamins and antibiotics. It is regarded as the most effective food for preventing and treating cardiovascular diseases in the elderly and maintaining vascular health.
7. Fermented soybean products have the effect of preventing and treating senile dementia. Acetylcholinesterase, an enzyme produced by the human body, breaks down neurotransmitters. Modern medicine believes its presence is related to the onset of Alzheimer's disease. In a joint study with Japanese experts, the author found that Chinese fermented bean curd has significant acetylcholinesterase inhibitory activity. This means that fermented bean curd is effective in preventing and treating senile dementia.